Olympiacos star Bruma says Sokratis has filled in his teammates about Arsenal's 'secrets'.
The Greek defender moved back to his homeland in January after his contract was terminated by mutual consent.
And the 32-year-old will come up against his former side in the Europa League last-16 in Athens on Thursday.
"He has told us some secrets, but I won't tell you about any of them," Bruma told Goal ahead of the first leg. "It's between us and Sokratis.
"Of course, he knows Arsenal's locker room better than anyone.
"He is a player with a lot of experience, he's played for Milan, Dortmund and Arsenal who are all great, great clubs.
"So Sokratis is a very good voice, he's been helping a lot in the locker room and he's been helping the team a lot with his experience. We are really pleased to have him here and I'm sure he's going to be a big help on Thursday."
